#5731 PTB *s-lum ⪤ *b/m-lu(m/ŋ) ROUND / ROUND OBJECT / HEART / EYEBALL

Several phono-semantically similar variants are to be grouped together in this etymon. Their center of gravity is ROUND OBJECT, as shown in various compounds for rounded body parts and inanimate objects. The variants with final ‑m and ‑ŋ are equally well-attested, even within a single subgroup (cf. Bruhn’s [2014] reconstructions for Proto-Central-Naga: PCN *m‑luŋ HEART / BE ROUND and PCN *ləm HEAD / HEART / MIND.

Bahing thym and Hayu thum ‘heart’ look as if they might somehow be related, although the initial dental stop is a problem.